The field of the present invention is portable chairs, particularly foldable or collapsible portable chairs.
Although portable chairs have long been known, a constant concern has been to construct portable chairs that are comfortable and durable, yet are capable of being easily compacted into minimal space and then readily reassembled. Various attempts towards this end are the following:
U.S. Pat. No. 2,564,915 to Nelson PA0 U.S. Pat. No. 3,695,702 to Ingellis PA0 U.S. Pat. No. 4,514,009 to Vanderminden et al.
As is true with other known collapsible or portable chairs, these devices may function adequately well, but they are each deficient in one or more respects. First, most portable chairs are only minimally compactable. Typically a "portable" chair continues to be unwieldy and to provide storage problems even in its folded or compacted position. Those chairs that thoroughly collapse usually provide a plethora of separate pieces which are easily misplaced and create an undesired challenge for reassembly. Second, many folding chairs are uncomfortable and are limited by little or no adjustability.
To some extent the collapsibility of portable chairs has been constrained by the types of hinges available. As a practical matter, in order to repeatedly fold a chair, flexible hinges must be employed that accept pivoting in more than one plane of movement; however, such hinges must be capable of being locked into position once the chair is fully assembled. Examples of previous attempts, to create locking hinges are U.S. Pat. No. 1,036,222 to Griffenberg and U.S. Pat. No. 4,160,607 to Reichon. Although these devices may function well in their particular applications, they do not solve the problems found in creating a fully collapsible folding chair. The hinge required in a fully collapsing portable chair needs to be quite flexible in the open position and strong enough to withstand the stresses of repeated distortions, yet resistant to all movement when in the locked position.
It is therefore an object of the present invention to provide a flexible locking hinge which can withstand the stresses inherent in fully collapsing a portable chair, yet provide a secure, unified structure when locked.
It is another object of the present invention to provide a portable chair that readily and thoroughly collapses into a compact easily transportable and storable single unit that is quickly and easily reassembled.
It is a further object of the present invention to provide a portable chair that is comfortable and allows for a full range of adjustability, from upright sitting to fully reclining positions.